Process for making heavy duty liquid detergent compositions

ABSTRACT

HEAVY DUTY LIQUID DETERGENTS IN THE FORM OF EMULSIONS WHEREIN THE ORGANIC ACTIVE IS MAINTAINED IN A DISPERSED PHASE, AND SAID DISPERSED PHASE IS STABILIZED IN A CONTINUOUS AQUEOUS PHASE BY A POLYELECTROLYTE. THE CONTINUOUS AQUEOUS PAHSE CONTAINS A BUILDER COMBINATION OF SODIUM TRIPOLYPHOSPHATE AND POTASSIUM NITRILOTRIACETATE.

United States. Patent 01 flee 3,591,508 PROCESS FOR MAKING HEAVY DUTYLIQUID DETERGENT COMPOSITIONS James M. Huggins, St. Ann, and Robert T.Jorgen, Bridgeton, Mo., assignors to Monsanto Company, St. Louis, M

O- No Drawing. Filed Dec. 7, 1967, Ser. No. 688,710 Int. Cl. (111d3/075, 3/26, 11/00 US. Cl. 252137 1 Claim ABSTRACT OF THE DISCLOSURE Thepresent invention relates to a heavy duty liquid laundry detergentcomposition in the form of an emulsion; more particularly, a phasestable heavy duty liquid laundry detergent composition containing asbuilders sodium tripolyphosphate, and potassium nitrilotriacetate in acontinuous aqueous phase, and containing the surface active agent in thedispersed phase which is stabilized in the aqueous phase by apolyelectrolyte.

Some of the advantages of liquid detergents well known in the artinclude, for example, freedom from dust and ease of use, particularly,in automatic dispensers and measuring devices found on many present-daywashing machines. Since liquid detergents are concentrated, packagescontaining them take up less space and are easier to handle. Beforewashing, liquid detergents can be used to treat heavily soiled spots andstains on fabrics.

To be as effective as a conventional heavy duty solid detergent, aliquid detergent must contain an adequate amount of builder, that is, anauxiliary agent used with a surface active agent to improve detergency.Desirable builders are inexpensive and compatible with other components,both organic and inorganic, normally found in detergents. Thepolyphosphates and pyrophosphates, as is well known, are used asbuilders in detergent compositions, the most effective member beingsodium tripolyphosphate. However, sodium tripolyphosphate is notgenerally used as a builder in a liquid detergent composition, mainlybecause of this compounds low solubility in an aqueous solution and itshydrolytic degradation to pyrophosphate and orthophosphate. Thepyrophosphates, especially potassium pyrophosphate, have been used asbuilders in liquid deter-gent compositions, because, among other things,of their high solubility in an aqueous solution; however, thesecompounds are not as effective and are more expensive than sodiumtripolyphosphate.

When moderate amounts of inorganic or organic builders (and/or otherinorganic salts) are used with a nonionic organic surface active agent,the temperature for phase separation is generally lower than roomtemperature. To prepare a homogeneous product containing an adequateamount of builder, either the nonionic surfactant is dissolved in thebuilder solution by a solubilizing agent, or the nonionic is allowed tovremain as a separate phase,

but this separate phase is dispersed and stabilized in the buildersolution.

It, therefore, would be an improvement over the art 3,591,508 PatentedJuly 6, 1971 to provide a liquid detergent composition containing anappreciable amount of sodium tripolyphosphate as a builder. It would bea further improvement over the art to provide a liquid detergentcomposition in the form of an emulsion which is phase stable andcontains a nonionic organic active and an appreciable amount of sodiumtripolyphosphate.

It is, therefore, a primary object of this invention to provide a heavyduty liquid laundry detergent composition, in the form of an emulsion,containing a builder combination which imparts improved performance tothe composition.

It is another object of this invention to provide a heavy duty liquidlaundry detergent composition in the form of an emulsion containingsodium tripolyphosphate and potassium nitrilotriacetate as a buildercombination.

It is another object of this invention to provide a heavy duty liquidlaundry detergent composition in the form of an emulsion containingpotassium nitrilotriacetate and an appreciable amount of sodiumtripolyphosphate as a builder combination.

It is another object of this invention to provide a heavy duty liquidlaundry detergent composition in the form of an emulsion which is phasestable containing potassium nitrilotriacetate and an appreciable amountof sodium tripolyphosphate as a builder combination.

Other objects will become apparent from reading the following moredetailed description.

The above objects can be accomplished by preparing a heavy duty liquidlaundry detergent composition in the form of an emulsion comprising acontinuous aqueous phase containing as a builder sodium tripolyphosphateand potassium nitrilotriacetate; a dispersed or internal phasecontaining as an organic active a nonionic alcohol-ethylene oxidecondensate; and containing a polyelectrolyte as an emulsion stabilizer.

The organic actives that can be used in practicing this invention arealcohol-ethylene oxide condensates of the general formula:

where R is selected from the group consisting of an alkyl containingfrom about 5 to about 20 carbon atoms and hydrogen, when both Rs arealkyl the total number of carbon atoms does not exceed about 20; x is anumber from about 3 to about 15. Some examples of alcohols which can becondensed with ethylene oxide include: hexane-l-ol, octane-l-ol,decane-l-ol, undecane-l-ol, dodecane-l-ol, tetradecane-l-ol,pentadecane-l-ol, octadecane-l-ol, nonadecane-l-ol, hexane-3-o1,octane-S-ol, dodecane-3-ol, pentadecane-3-ol, nonadecane-3-ol,heptane-fi-ol, tridecane6-ol, hexadecane-6-0l, dodecane-S-ol,tetradecane-lO- ol, octadecane-14-ol, 3-methyl hexane-l-ol, 4-methyldecane-l-ol, S-methyl tetradecane-l-ol, IO-methyl octadecane-l-ol,S-ethyl heptane-l-ol, 7-ethylnonadecane-1-ol, 9- ethyl tridecane-l-ol,ll-ethyl heptane-l-ol, Z-methyl hexane-3-ol, S-methyl decane-S-ol,7-methyl tetradecane-8-ol, ll-methyl octadecane-l4-ol, -6-ethyloctane-4-ol, 9-ethyl pentadecane-lZ-ol, ll-ethyl octadecane-lS-ol, andmixtures thereof.

In practicing this invention, preferred alcohols include dodecane-l-ol,tridecane-l-ol, tetradecaue-l-ol, pentadecane-l-ol, and mixturesthereof. The majority of those alcohols listed hereinbefore and used inthe novel compositions of this invention are biodegradable and arepreferred as such. However, it is to be understood that nonbiodegradablealcohols can be used if circumstances warrant such a utility.

The number of moles of ethylene oxide condensed with the above alcoholscan vary from about 3 moles to about 15 moles, and a preferred range isfrom about 8 moles to about 12 moles.

The aforementioned alcohols can be used in amounts from about 5% byweight to about by weight of the liquid detergent composition andpreferably from about 8% by weight to about 12% by weight. The meaningof the term liquid detergent composition as used herein generallyconnotates a composition containing actives, builders, polyelectrolytesand other non-essential ingredients such as optical brightners, pigmentdyes, corrosion inhibitors, perfumes, etc. Consequently, the weightpercentages given herein are predicated upon the total weight of suchliquid detergent composition.

The present invention employs a builder combination of potassiumnitrilotriacetate and sodium tripolyphosphate. By using this buildercombination an appreciable amount of sodium tripolyphosphate whichresists hydrolytic degradation at elevated temperatures can beincorporated into a liquid detergent composition. As shown by theexamples hereinafter set forth, the novel compositions of the presentinvention perform well as heavy duty detergents and are a significantimprovement over the prior art detergents.

The exact action which potassium nitrilotriacetate exerts on sodiumtripolyphosphate is not known; however, it has been theorized thatpotassium nitrilotriacetate acts in some manner as a solubilizer forsodium tripolyphosphate. It is to be understood that any theories orideas set forth herein are merely speculative and are not to beconsidered limitations on the invention.

Sodium tripolyphosphate can be used in amounts from about 5% by weightto about 13% by weight of the liquid detergent composition andpreferably from about 10% by weight to about 12% by weight. Potassiumnitrilotriacetate can be used in amounts from about 5% by Weight toabout 30% by weight of the liquid detergent composition and preferablyfrom about 10% by weight to about 16% by weight.

The polyelectrolytes that can be used in preparing the present inventioninclude the copolymer of maleic anhydride and ethylene and the copolymerof maleic anhydride and methylvinylether. The specific viscosity of suchpolyelectrolytes can be determined by using ASTMD44546T Method B; a copyof this procedure may be obtained from United States of AmericaStandards Institute, 10 E. 40th Street, New York, N.Y., 10016.Essentially, this method entails dissolving 1% by weight of thecopolymer in 99% by weight of dimethylformamide and subsequentlymeasuring the specific viscosity of the resulting solution at C. usingan Ostwall Viscometer. The following reactions illustrate the formationof the respective copolymers:

A wide variety of copolymers which impart a low viscosity to thefinished product can be used to prepare stable emulsions of the presentinvention. It is undesirable to prepare a liquid detergent compositionhaving a high viscosity since it will not flow freely from its containerand thus would be commercially impractical. Consequently, it ispreferred to utilize copolymers which give the final product (i.e. theliquid detergent composition) relatively low viscosities of from about250 cps. to about 700 cps. at room temperature, i.e. about 20 C. Thespecific viscosities of the copolymers of maleic anhydride and ethylenewhich can be used in practicing this invention range from about 0.1 toabout 1.2 and of maleic anhydride and methylvinylether range from about0.5 to about 3.0. These copolymers can be used in amounts from about0.2% by weight to 2.0% by weight of the liquid detergent composition andpreferably from about 0.7% by weight to about 1.1% by weight.

Other ingredients which can be used in the novel compositions of thepresent invention, in addition to the abovementioned essentialcomponents, include compounds such as alkali metal silicates, sodiumcarboxymethylcellulose, dyes, and fluorescent dyes, etc. The quantitiesof these other ingredients with the exception of the abovementionedessential components are not critical and persons skilled in the art candetermine the proper amounts for their own particular requirements. Thequantities of some of these other ingredients include, for example,sodium silicate in amounts from about 3% by weight to about 10% byWeight of the liquid detergent composition; sodiumcarboxymethylcellulose in amounts from about 0.5% by weight to about 4%by weight of the liquid detergent composition; pigment dyes in amountsfrom about 0.05% by weight to about 0.08% by weight of the liquiddetergent composition; and fluorescent dyes from about 0.1% by weight toabout 0.8% by weight of the liquid detergent composition.

In practicing the present invention, it is desirable to e'mulsify theessential ingredients in order that an organic active can be maintainedin a concentrated salt solution (usually of inorganic and/or organicbuilders, corrosion inhibitors, antideposition agents, etc.) without theimmediate separation of the organic active. The above process permitsthe nonionic to remain in a dispersed phase, and the aforementionedcopolymer stabilizes the dispersed phase in continuous phase whichcontains the builder combination.

Generally speaking, the method for preparing the novel compositions ofthe present invention can be divided, for the sake of clarity, intothree distinct steps, namely, (1) hydrolysis, (2) esterification and (3)pH raising.

The hydrolysis step of the present process must be performed while thecopolymer is dispersed through (or maintained completely in contact withwater therein in some manner) a liquid aqueous medium having a pH belowabout 6, preferably from about 1 to about 4. In addition, thetemperature of the acidic aqueous medium or solution is maintainedbetween about C. and about 85 C. (preferably between about C. and C.)for a period of time which has been found to vary depending upon thespecific viscosity of the particular copolymer being employed, forexample, the copolymers of maleic anhydride and methylvinylether, have ahydrolysis time that ranges from about 10 minutes to about 50 minutes.At temperatures below 50 C., the necessary type of hydrolysis of thecopolymer does not effectively occur, or Occurs so slowly as to make anyprocess resulting from use of such low hydrolysis temperaturescommercially undesirable. Only partial hydrolysis of the copolymeroccurs during this step.

The esterification step of the present invention process involvesessentially the intermixing of a quantity or an amount of an organicactive that is capable of reacting with the hydrolyzed groups(apparently the free carboxylic acid groups) on the partially hydrolyzedcopolymer (resulting from the hydorlysis step described above) to formester groups. It is desirable that the amount of the organic active usedduring this esterification step be within the range of from about byweight to about 15 by weight of the liquid detergent composition. It hasbeen observed during the experimentation on the present invention thatit is desirable to have more than the amount of reactive surfactantnecessary to saturate the aqueous medium during the esterification step.The amount of organic active used is thus preferably within the range offrom about 8% by weight to about 12% by weight of the liquid detergentcomposition during the esterification step. Furthermore, the temperatureand the pH of the aqueous medium are variables which are controlled forcertain periods of time during the esterification step. Morespecifically, the temperature is maintained within the range of about 50C. and about 85 C., preferably between about 55 C. and about 75 C., andthe pH of the aqueous medium during esterification is continuously heldbelow about 6, preferably between about 1 and about 4 during suchperiods of time.

The period of time referred to with respect to the esterification stepof the preferred process can vary to some extent, the particular rangebeing primarily determined by the particular copolymer involved, forexample, the esterification time of the copolymers of maleic anhydrideand methylvinylether ranges from about 10 minutes to about 35 minutes.Only partial esterification of the acidic (partially hydrolyzed)copolymer occurs during the above-described esterification step.

During the pH raising step, the pH of the aqueous medium (containing thepartially esterified copolymer organic surface active agent mixture) israised to at least about 10, thereby preventing any additional acidichydrolysis or esterification from occurring. Potassium hydroxide inamounts from about 3% by weight to about 12% by weight of the liquiddetergent composition is a preferred compound used to raise the pH.Other compounds can be used in conjunction with the potassium hydroxideto and in raising the pH and some of these include, for example,potassium nitrilotriacetate in amounts from 8% by weight to about 15% byweight of the liquid detergent composition, sodium tripolyphosphate inamounts from about 10% by weight to about 13% by weight of the liquiddetergent composition, sodium carboxymethylcellulose in amounts fromabout 1% by weight to about 3% by weight of the liquid detergentcomposition.

The processes used to prepare the novel compositions of the presentinvention are disclosed in US. Pat. 3,457,176 filed Oct. 16, 1964 andwhich is assigned to the same assignee of the present invention.

A preferred embodiment of the present invention comprises (1) from about8% to about 12% by weight of organic actives, such as, dodecane-l-ol,tridecane-l-ol, tetradecane-l-ol, pentadecane-l-ol, etc., (2) from about10% to about 12% by weight of sodium tripolyphosphate, (3) from about10% to about 16% by weight of potassium nitrilotriacetate, (4) fromabout 0.7% to about yde, from about 7% by weight to about 15% by weightof 1.1% by weight of the copolymers of maleic anhydride and ethylene, orthe copolymers of maleic anhydride methylvinylether and othernon-essential ingredients including, for example, from about 0.01% byweight to about 0.03% by weight of a pigment dye, from about 0.1% byweight to about 0.3% by weight of a fluorescent dye from about 7% byweight to about 15% by weight of potassium hydroxide, from about 0.5% byweight to about 3.0% by weight of sodium carboxymethylcellulose and fromabout 6% by weight to about 10% by weight of sodium silicate. Liquiddetergent compositions containing the above components, have excellentwashing abilities and can be used in automatic devices on modern washingmachines.

In the following examples, which illustrate some of the preferredembodiments of the present invention, all parts are given by weightpercent of the total composition unless otherwise stated.

EXAMPLE I A novel composition of the present invention was preparedcontaining the following ingredients:

Material: Percent Water 1 46.3 Pigment dye 0.02 Fluorescent dye 0.20

Methylvinylether maleic anhydride (specific viscosity 1.5-2.0) 0.8Nitrilotriacetic acid 3.00 Potassium hydroxide (45% by weight) 2.90 O -Cprimary alcohol+9 moles ethylene oxide 10.00 Potassium nitrilotriacetate(51% by weight) 14.10 Sodium tripolyphosphate 12.0 Sodiumcarboxymethylcellulose (65% by weight) 1.0 Potassium hydroxide (45 byweight) 4.4 Sodium silicate (1:24 47% by weight) 7.8

1 2.5% excess water added for evaporation.

Into a six blade turbine mixer having a tip speed of 1000 feet perminute were charged the water, which had been preheated to 65 C. and thedyes. The copolymer of maleic anhydride and methylvinylether was slowlyadded and mixed for about 30 minutes to bring about hydrolysis.Nitrilotriacetic acid and potassium hydroxide were added 'to form thehalf salt of potassium nitrilotriacetate. A mixture of (C -C primaryalcohols condensed with nine moles of ethylene oxide which had beenpreheated to 65 C., was gradually added and agitated for about 20minutes to bring about esterification. Potassium nitrilotriacetate wasslowly intermixed keeping the temperature from about 65 C. to about C.,then sodium tripolyphosphate. Sodium carboxymethylcellulose, potassiumhydroxide and sodium silicate were separately added and mixed for about15, 2 and 10 minutes, respectively.

The above mixture had a pH of about 11.9 and an initial viscosity of 620cps. as measured by a Brookfield Viscometer using a No. 3 spindle at 60rpm. for 30 seconds. The viscosity was well within the acceptable rangehereinbefore discussed.

The phase stability was determined by a centrifuge test. This test wasdeveloped to simulate prolonged storage conditions because of theimpracticality of testing detergents under actual conditions. Theresults of this test have been found to correlate with data taken fromactual tests under prolonged storage conditions. The test involvescentrifugation of the material in a calibrated glass centrifuge tube. AClay Adams Centrifuge is used at full speed (1000 gravities) for 60minutes, at a temperature of about 27 C. Formulations that exhibit lessthan 6% (by volume) visible separation in this extreme test areconsidered acceptable and will exhibit excellent stability against phaseseparations under normal storage and handling conditions, while thosethat exhibit more than 6% separation are not acceptable. Twelvemilliliters of the product of Example I in a calibrated centrifuge tubewere centrifuged at a full speed (1000 gravities) in a Clay Ada-msCentrifuge for one hour. Only 4 volume percent of clear solution wasobserved at the bottom of the centrifuge tube. Thus, separation in thistest was only 4 volume percent, and, therefore, said product is ratedacceptable in accordance with the foregoing discussion.

A comparison of the washing performance of the novel compositiondescribed in Example I was made with that of a conventional heavy dutyliquid detergent of the following formula:

1 Ethylene oxide.

Data is tabulated in Tables I and II. The testing method utilized ismore specifically described in the Journal of the American Oil ChemistsSociety, Volume 42, pp. 723- 727, August 1965, which is herebyincorporated by reference.

TABLE I.-ARd GRAYNESS Temperature 0., 50 p.p.n1. water hardness ARd ARdARd Concentration, percent 0. O. 0. Conventional detergent, perccnt 10.0 12. 2 12. 2 Example I, percent 10. 8 13. 4 12. 6

TABLE II.Ab YELLOWNESS Temperature 10 C., 50 p.p.m. water hardness TableI gives the readings taken on a Gardner Color Difference Meter comparingthe soil-removing ability of the respective detergents at differentconcentrations. The higher ARd reading indicates the bettersoil-removing ability. As can be seen from Table I, at each respectiveconcentration, Example I exhibits a substantially improved soil-removingability as contrasted to the conventional liquid detergent.

The ability to decrease fabric yellowness is indicated in Table II by ahigher Ab reading. As can readily be seen from Table II, the novelcomposition described in Example I exhibits a superior performance thanthat of the conventional heavy duty liquid detergent.

The following are typical examples of liquid detergent compositions ofthe present invention which exhibit superior washing performance wereprepared according to the procedure outlined hereinbefore.

EXAMPLE 11 Percent Water 1 46.3 Pigment dye 0.07 Fluorescent dye 0.2Ethylene maleic anhydride (specific viscosity 0.6) 0.8 Nitrilotriaceticacid 3.0 KOH (45% by weight) 2.9 Dodecane-l-ol and Tridecane-l-ol-9 E.O.10.0 Potassium nitrilotriacetate (51% by weight) 14.1 Sodiumtripolyphosphate 5.0 Sodium CMC (65% by weight) 1.0 KOH (45% by weight)4.4 Sodium silicate (1:24, 47% by weight) 7.8

1 2.5% excess water added [or evaporation.

8 EXAMPLE III Percent Water 1 45.2 Pigment dye 0.02 Fluorescent dye 0.20

Methylvinylether maleic anhydride (specific viscosity 1.5+02.0) 0.90Nitrilotriacetic acid 3.00 KOH (45% by weight) 2.90

4-methyl decane-1-ol-10 E.O. 11.00

Potassium nitrilotriacetate (51.4% solids) 14.1 Sodium tripolyphosphate12.0 Sodium CMC by weight) 1.0 KOH (45% by weight) 4.4 Sodium silicate(1:24, 47% by weight) 7.8

1 2.5% excess water added for evaporation.

EXAMPLE IV Percent Water 1 44.3 Pigment dye 0.02 Fluorescent dye 0.20Ethylene maleic anhydride copolymer (specific viscosity 0.6) 1.00Nitrilotriacetic acid 3.00 KOH (45% by weight) 2.90

7-ethyl nonadecane-l-ol-lO E.O 11.80

Potassium nitrilotriacetate (51% by weight) 14.1 Sodium tripolyphosphate12.0 Sodium CMC (65% by weight) 1.0 KOH (45% by weight) 4.4 Sodiumsilicate (122.4, 47% by weight) 7.8

1 2.5% excess water added for evaporation.

Cross-linked copolymers of ethylene maleic anhydride can be used asstabilizers in the present invention in addition to the linearcopolymers of maleic anhydride described hereinbefore. The linearpolymers that result from polymerizing maleic anhydride with ethylenecan be crosslinked with diamine and alkylene polyamine or a diolefinicmaterial such as an ether or a hydrocarbon etc. Examples of polyamineswhich have been found to be particularly useful are diethylene triamine,triethylene tetramine, tetraethylene pentamine, and higher molecularweight polyethylene polyamines. Preferred diolefinic crosslinkingmaterials include divinyl benzene, diallyl ether, vinyl crotonate,diallyl esters, and the like.

The solution viscosities of these cross-linked ethylene maleic anhydridecopolymers are determined by preparing a 1% solution in distilled waterof the cross-linked ethylene maleic anhydride copolymer adjusting the pHto 9 with ammonia and reading the viscosity on a Brookfield LVTViscometer having a No. 4 spindle and a totational speed of 6 rpm. Thetemperature is maintained at about 25 C. The cross-linked copolymers ofethylene maleic anhydride that can be used in the present invention havea solution viscosity that varies from about 10,000 cps. to 180,000 cps.For example, 0.8% by weight of ethylene maleic anhydride copolymercross-linked with vinyl crotonate having a solution viscosity of about10,000 cps. to about 20,000 cps. can be used to stabilize the detergentactive in the continuous aqueous phase.

What is claimed is:

1. A process for producing a heavy duty liquid detergent composition, inthe form of an emulsion, said process consisting of:

(A) Charging 46.3 parts by weight of water, 0.02 part by weight of apigment dye and 0.20 part by weight of a fluorescent dye into a sixblade turbine mixer having a tip speed of 1000 feet per minute, saidwater having been preheated to 65 C.;

(B) Slowly adding a copolymer of maleic anhydride and methylvinyletherhaving a specific viscosity of 1.5 to 2.0 to the mixer and mixing for 30minutes to bring about hydrolysis;

(C) Adding to the mixer 3.00 parts by weight of nitrilotriacetic acidand 2.90 parts by weight of 45 potassium hydroxide to form the half saltof potassium nitrilotriacetate;

(D) Preheating a mixture of C -C primary alcohols condensed with ninemoles of ethylene oxide to 65 C., adding this condensation product tothe mixer gradually and agitating for minutes to bring aboutesterification;

(E) Slowly intermixing 14.10 parts by weight of 51% 10 aqueous potassiumnitrilotriacetate and 12.0 parts by weight of sodium tripolyphosphatewhile maintaining the temperature at from about C. to about (F) Adding1.0 part by weight of 65% aqueous sodium carboxymethylcellulose andmixing for 15 minutes;

(G) Adding 4.4 parts by weight of 45% aqueous potassium hydroxide andmixing for 2 minutes; and

10 (H) Adding 7.8 parts by weight of 47% aqueous sodium silicate andmixing for 10 minutes.

References Cited 5 UNITED STATES PATENTS 3,457,173 7/1969 Huggins 252-3,328,309 6/1967 Grifo et a1. 252137 OTHER REFERENCES STPP for ModernDetergents, by Dr. J. D. McGilvery, in Soap & Chemical Specialties,December, 1964, pp. 241, 243 and 254-257.

15 LEON D. ROSDOL, Primary Examiner D. L. ALBRECHT, Assistant ExaminerUS. Cl. X.R. 252-89, 135

